Code reuse and license compliance

[nickdesaulniers]

@martynsmith , I modified node-irc and am using it clientside in an Firefox OS IRC client app. Our new/young/immature TCP socket interface has some differences from Node (which I'll argue to resolve internally), but other than a few lines to shim out the differences it works! We include my fork of node-irc as a git submodule.

I had two quick questions:

1. We've included a copy of the GPLv3 and added a license header block to our code, acknowledging your copyright. Is this sufficient?
2. The modified fork isn't in shape to be contributed back upstream. Under the GPL, am I required to upstream my changes?